The performance of the semiconductor device is significantly affected by the doped well region, it is especially important to control the property of the doped well region as the critical dimension has been reduced to less than 55 nm. The property of the doped well region can be affected by various factors, such as the ion implantation dose, the ion implantation depth, the ion implantation angle, and the ion implantation diffusion, etc. However, due to the lack of the effective evaluation of the ion implantation diffusion, it is difficult to control the effects on the performance of the semiconductor device by the ion implantation diffusion.
In the subsequent thermal annealing process for restoring the crystal lattice, the ions implanted into the doped well region will diffuse, usually lateral diffuse along the damaged crystal lattice. The lateral diffusion may have a greater effect on the performance of the semiconductor device. For example, the ions in the N-type doped well region will diffuse into the P-type doped well region under heating, which may seriously affect the performance of the semiconductor device as the ion diffusion region of the N-type doped well region may cause an electricity leakage in the PMOSFET.
So far the lateral diffusion of the implantation ions of the doped well region is measured via the WAT (wafer acceptance test) and electrical property test. However, since the multiple manufacturing processes performed after the ion implantation diffusion may also affect the measurement results of WAT and electrical property test, the lateral diffusion of the implanted ions of the doped well region is difficult to measure accurately, and the recycle period of the manufacturing processes is extended.
Consequently, an effective measurement of the lateral diffusion of the implanted ions in the doped well region of the semiconductor device is needed.